#include <opencv2/opencv.hpp>
#include <iostream>
#include <math.h>

using namespace std;
using namespace cv;

namespace chapter033 {

	Mat src, gray_src;
	int threshold_value = 80;
	int threshold_max = 255;
	const char* output_win = "image moents demo";
	RNG rng(12345);
	void Demo_Moments(int, void*);
	int chapter033(int argc, char** argv) {
		src = imread("test.jpg");
		if (!src.data) {
			printf("could not load image...\n");
			return -1;
		}
		cvtColor(src, gray_src, CV_BGR2GRAY);
		GaussianBlur(gray_src, gray_src, Size(3, 3), 0, 0);

		char input_win[] = "input image";
		namedWindow(input_win, CV_WINDOW_AUTOSIZE);
		namedWindow(output_win, CV_WINDOW_AUTOSIZE);
		imshow(input_win, src);

		createTrackbar("Threshold Value : ", output_win, &threshold_value, threshold_max, Demo_Moments);
		Demo_Moments(0, 0);

		waitKey(0);
		return 0;
	}

	void Demo_Moments(int, void*) {
		Mat canny_output;
		vector<vector<Point>> contours;
		vector<Vec4i> hierachy;

		Canny(gray_src, canny_output, threshold_value, threshold_value * 2, 3, false);
		findContours(canny_output, contours, hierachy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));

		vector<Moments> contours_moments(contours.size());
		vector<Point2f> ccs(contours.size());
		for (size_t i = 0; i < contours.size(); i++) {
			contours_moments[i] = moments(contours[i]);
			ccs[i] = Point(static_cast<float>(contours_moments[i].m10 / contours_moments[i].m00), static_cast<float>(contours_moments[i].m01 / contours_moments[i].m00));
		}

		Mat drawImg;// = Mat::zeros(src.size(), CV_8UC3);
		src.copyTo(drawImg);
		for (size_t i = 0; i < contours.size(); i++) {
			if (contours[i].size() < 100) {
				continue;
			}
			Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
			printf("center point x : %.2f y : %.2f\n", ccs[i].x, ccs[i].y);
			printf("contours %d area : %.2f   arc length : %.2f\n", i, contourArea(contours[i]), arcLength(contours[i], true));
			drawContours(drawImg, contours, i, color, 2, 8, hierachy, 0, Point(0, 0));
			circle(drawImg, ccs[i], 2, color, 2, 8);
		}

		imshow(output_win, drawImg);
		return;
	}
}